SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5ad1a1beb38de892ed3abac1db883c331112bb54d471fd8a3a61eed9ac2f34e' 
  AND token = 'cnkV/0T8oEt+qv134LvSvUoU/UpLSO4oLweWqZIELBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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