SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56a9d862fa82dd6f322161224ac3f57e2639370742345bec2791cccf4420199a' 
  AND token = 'tsaiDAY5o8gkMW+X0Doj8oaKpCav4cjm/OgRUNCjYrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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