SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e2aeeabc2e1579f8075313c3ba53ed2eb682bb1517fec6351a64738ee6b666a' 
  AND token = 'EFrX5cdN9nqbp8ueDRHA9aHWMCtehdd6GdoUx6uvXGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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