SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '657c3df7d91bcea340b4bdce9ed1877d01f396ddebae3780011e43100ee230a1' 
  AND token = 'gr6NHE/HEvQQDKpcVCqThYk+EdV22zWKA4CMWSuT5A4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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