SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '064bfa3792ba7290ba95afe7092047a1cfcc2a6468bf162956de3b03a05c90ae' 
  AND token = 'vX3AuLu9Y2Gkkdyn2Gn8LI2zEces+qXfaJ+Aw9CMbm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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