SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ea330e98429f9b92e043781a06fe97ef27cf70143c34c15de925a22e1d3dd52' 
  AND token = 'o076V0QBof+fGC2NzlfH9M6Z57vqhbgXdp2L/bvMwqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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