SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3cc6fed0e8da45f3e5bc7825df865d99bdbe8a2a29d52965615da9250c80ee45' 
  AND token = 'uD0TzwbykTSJ+7YJStmy8Qz+Z+/b2B0Iw8kzdwKaZfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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