SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95349dba67ab6832f1585c51d0f60dbc503c8417eb81f6a1709b482237b97796' 
  AND token = 'osDcLCQ2FpT7qhCgEkwsCIstaFFXAnpFZJ/EvBr+5RM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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