SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c5f30f05ecb0dd4a58eafc1401cd02231f5431b839e2a9942b310642d73e659' 
  AND token = 'QO9IiWWHYS2+FZZImV82WytkoKIgCClpDEKECvOo7iY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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