SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fce2e62097ab5f59c1a2c75e8e35d1013f81d3b469eecaa69010632ec4776778' 
  AND token = 'JD1Fql93SGhdOQZ9rmeIYgtHC+Gh2XFqYWGj8Ur/uz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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