SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3cd518595c5cae8fdd39686ca1208ed776199b02d1192c3543a21d173ecf4ea' 
  AND token = 'N1dQE3kcC1jT+2eLI22H2kjSfhgi1cPLVzHB2UerAQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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