SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06e85e15a8fd9ad0276edec4e95bf55df4f27476693afc29dab2eccfc8859259' 
  AND token = '4XLqRkLJxuiz5H37ITTRgtlexHSA2nxSiQg237ct1ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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