SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cdaac2eb7dd81699d317a58932633945e4f2e22243589370ea7925b1f372872' 
  AND token = 'tLo3ndUH87Ont4oBqz5/2gHt7WHFW6E+oYTWaDSURIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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