SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fd9ae144fdbe1333be5a2cd26629472dfba891f5a28df473ab740aaaef260ef8' 
  AND token = 'a1kzZg3WF160XTyhidLHZWx4gd+DHJ0h8Ldx4ZQC8e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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