SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deb2e7a246e2273945680a3d0411cd82ba3d7486d8c353216ae7c1d40e1f676b' 
  AND token = 'tGLPwECIXPwTj0aCGYVvjfJ4MiBnjIL/U/Wz28Fb6AA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}