SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e84493a80215eb42cb65e6e81b97883cb25865b6c4b06ad3abcb1bfd26b54611' 
  AND token = 'PlYr1ZdwK7wAKuGCDYKjpy/0UPy5Q9v+ugFCGI7I7Qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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