SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea4294dc0199bbceef961ebba553a979c59fe7f493df41b0d6a739dcee4f1d63' 
  AND token = 'MGLIULnQY46gDbyq+/5wyCemyl/Uoze8CsLmmbs5/VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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