SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48d6908979ffc60e9965f99dcc83ba4d3284588d85b65e6ac3ef71a5b81943ed' 
  AND token = 'AVc+f4b8TN22vkJ8CiPhnzf0TgP/8YVMBPmwFuHZezE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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