SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9e5b1b9bcda34dc2fdd833e7f33e721b3be0ac4fabaeaedb05d4d616ba82303' 
  AND token = 'yt+Ds0flcjSMmOdhaYQf0S3t2cbrJa716qReONslRA4=' 
  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"
    }
  }
}