SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bb522a055a986dd93d0bde4aeb94ed46ee7b15ff6fa597a8fcd5892d34a0a0b' 
  AND token = '2QPQuSRBCmyfgYfsZotocN0kgvnjHuqqwiPTZW/Hzi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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