SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '780db8ee3cc93af3b666b2e2091db6764ee79e2467d3642441a8cb082ee54b69' 
  AND token = 'p3iT7gp0OrcUAxKwbS3c0LN6Aa6AcBei7aPDkVsauQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}