SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c970765924cfc7e89c0670d646f443ec307d7dad817d35f976aefe5005b14f0' 
  AND token = 'irmu/jAgZyTtU54SrrpDZcpdfjJgWIWUD+puIderxfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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