SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7317a5e3e43e6843c3a22213a54d8bb8f23b8272a82dec944231693ceb05eee1' 
  AND token = 'A64oJ0Dh9/HjDYnCnlbcOoM+KRqhIjwF2WWwrWheg3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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