SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfbe55ba3294cee889d3775ea4c1401d6ab4e443f1be47e495418a8320b2a22f' 
  AND token = 'tSfmQu9RYuSqQ3XbwKEwvrruqbhg6xmUznwGKTBObiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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