SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92c5890798bd4e52245a4d0697d43d41385f319a198b394a088116786d37eb60' 
  AND token = 'WPMKDA7mM0OIwzM7rsHSPkoQJkQ05Atx+WY3nGpGtUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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