SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ebecf2c0032b3fb4b5bdf3520d0fd46f54e64757094abbf53140530a13abf23' 
  AND token = 'YnfOykb9cBCY1lpSKwW/QaUYvrni0xJ+JiiV0TpdMDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00071

JSON explain

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