SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd416a0d32961a57e67f63171932f9fd9f5bee888233dce37bbceebcbcee4674b' 
  AND token = 'ywNoMf3S6SdEosZEs5wyh8McdTfdA1S9nd3KUdJK+y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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