SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '79abbbf1db4489caab2ac6e7d4a8ddb0b0045e82a2bfc864b8f0a3a501184130' 
  AND token = 'z9ffdc56W2I15UTEtvPQ3NOKD/UuES7qrQCKBQWVWx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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