SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5843620529cd2bdfc8d6a7faf44ec561c3a08759e3fa0c927eb1d605642ccd34' 
  AND token = 'uL1vnKmuDPijGI5BzIEHCQ6T0kFWelZPK7E4og/bXnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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