SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '19c3d833fb45829d0cd95f1127473e4a6000de1e050bb774eb60de36945e635e' 
  AND token = 'vizGEh5m5SHC6BywVUPQpq2OhMqTFC+OTDcUFeQOTQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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