SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce4b3d4dcb45d8e9fd0eb82f636c0e420be715721349c241638c9629221dec9b' 
  AND token = 'JFEga7ZTSk6slACzFx/Qf/uzEM3+yKr2/UcbpYZ1n0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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