SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7a9e09cf1bb924e7284da8c441da077def8b8a1c1e25b3b3627338fc61e39bb' 
  AND token = 'SnJhVun2ufdGnA1phfFjP9Z+YWiWukQFDqrxalG9KFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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