SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '742a900f868f37b8e2423155b3b229d1f2ee1875fd21dcc5e4bd810b822ea3ae' 
  AND token = 'JRjydo4PowaqU1LEtDcSvCswd9660FSirRQuG5lkeaE=' 
  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"
    }
  }
}