SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce28bf14b7a42eb4d679e5ede0f4e16eaeaf37067b19c35125047b934a81aae2' 
  AND token = 'W0eVQ8l5jSFTshqzpkPtYmNW7Bk3/2yaMzm0s8dkfUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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