SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fbe1f14c38746f07ec55844d416f04ea2ef729979a8996b62f720b4f315ce2c' 
  AND token = 'Bn88K6MjggboG1zPsXl8HiwtzUGcT6hHgvO3VH2Nm80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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