SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe884bc0982be36a6ab5b01a0f2d00ef027acdca90e880b95d5fac87be5d3cba' 
  AND token = 'RhfCSE/0jJ3woi3c7WWnGZ47F2t/7tCyoO4bVkuiYu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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