SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5265cf96c2ee54dd30a154eac4dda2981d916a38741fc9f46daa1767932b617' 
  AND token = 'RhocgCDzAE88fse0Kx7Hp/MAMGrhEptgd+b0SPrv8m8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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