SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3141f726b687ac35da4153e171e2984bafb9cdc1db383523a941e62881511497' 
  AND token = 'R9mR/y1oo2bb9ZjbtjkizFKWF+6Vz6GeGgpBqzVirs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}