SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3b96d7d5c3ff71862e36be07e18e961ff122ccab5ea9ca2bcfd221959d26043' 
  AND token = 'MbsoXXJrPR/+TeVrC8NG8CgmcKernMBYhYw5hjSA53I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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