SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50976c47fc499f6e5b225f71741196fdbd60ef3227858392be4ff2ee99fb69e8' 
  AND token = 'FfVPRaCKyUInLT/dzbGNf5VqkHhFUHRF8m5vidNCpMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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