SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1a9034fea5797920ebef9064aa083587928b0d99d8187a26e07c8bbd3b086ab' 
  AND token = '4NhaRCctYDML+lb3Rb4/PCrpZ22+ydpTrJFCgchTOhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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