SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13b615ddcef9c06672a8a2f9c4cebc2500feaaeeb240e7dae22460bdc86b41f0' 
  AND token = 'R84evEI77KRnulGKX5XCu3pvk6LeGTu7AxpA78UXgys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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