SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4627c16121d13aafc4da158a2df000cafa26614f2ba000021530072e160c3c3' 
  AND token = 'taH/bE/YTO0ZuEyRbMZHg328H8wRCG03pmf/ok1UYRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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