SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c607946ae6245279e9b6093d2a1174d2a8df02a9b0f2360dd987125d5171db95' 
  AND token = 'FgPUZL0wGhjxln26l+FNk1BbtlBOMNu4ntlNCCMOfkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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