SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17e851a3af1b416cb67010c6a44baa4a56a28e145f0b12d8be6642d6d2b27c3c' 
  AND token = 'jIhTo4kDjXBCNg4R5Nc0u3zQOOXesnyC87o81kpugFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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