SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d9ed450cd71a7e7ab947fa90385b4d92072edccd15966814a0b317b83febf40' 
  AND token = '/z9WlB6m+KQIaFxvuDHsAQHzjDqGKL0LIM5eKxQI2Eg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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