SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3afc2fd3d5fd3ad73873fc0973c8e3ccd15c4b4e1c923f44b6cd25097c3d9154' 
  AND token = 'g8X+hV4LEXFlZsXBbnIh/C4uqe+4EwISFGSfUXpP7VQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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