SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29bbba15aa3f646c9acaffe8c01663b13f3af1b7b5bc6a6e5d18769cd6b1caa7' 
  AND token = '0Qf4lJGy/uOOuD/EU4YjHniyJLIv/CThA+ZwhRC3PLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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