SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '159eab4b209812a2c430a142a34f0d0eefbb4079a0e3fecaf453518f22aa51dd' 
  AND token = 'C981HZfXevQNTd13aRwOTZNLWfZRb5Z8dzP3M4EBbl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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