SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f39129440528e81df0fd0c25d96f16bc31c460f49b275f46878bb040a9c11f06' 
  AND token = '/idYO7+SEkT/j+FlZ2mW/EofUkz0NAaT8ssRq6LzlnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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