SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a87d397b66057584068b7ebe3f0472026b3349898463725b6cd832f163fbc283' 
  AND token = '28LmgaBs0vb+g7QqyE89ve4L7MygbPAO22QeaY5uJj4=' 
  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"
    }
  }
}