SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0204322764b8f479739dd84c8a7975f01ba2937652544689a4ed3058fbf5308' 
  AND token = 'wH9qvTrr9XlaA/Bpf+VIwKzl6tJXULUNm8+u8w4aOcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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