SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53155ae7e9e308fab8a0b86b964030a361166b7903e19c432795d322506debb3' 
  AND token = '2rr/QLpfzRp+yrtxwf4W7xGFpwUoq5QLOBT0t+yOkWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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