SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7277eaf43c95bd1803457ac00d18a2289c7e9d322c4558b42210423e585c6d84' 
  AND token = 'nYYNSC0lBDjTZcpFfXXaaDBBGTTlBjXSX6V28JxkPLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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