SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7be3825382081fd03c0e823122c3a32da4833bfaa830a8066cbb1f7ebcd04ed9' 
  AND token = 'M2Dsxt8f2hBYhfex3RbcpfJDa4rTG4HHzUc4SSb/52s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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