SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '754da03a2f200b0499d841f4180c1fd8cbef9aef6e1699e5ececb7a0afc97a55' 
  AND token = 'GJ0ApMqpxWgrQFgSeE7Rpr7roAiO5bvRWTObNY8Y3Go=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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