SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf1e0ec85994aeca7d4fa0942534d1a378dadefce224f5947d1348dc62be2739' 
  AND token = 'V+j3/5j4yRgjWKkS18t/QbnwkYnOpN9kqBPwwK2jYVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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