SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82f501099dc474d32fd5bdd8dc0d3e1879647873e8ab298933bce4172e0fec09' 
  AND token = 'Uf53Tk3NQHyA9vIFBmJ4iUbdPfV0ZPHqiYL+x81VVak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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