SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d3bf34a17cbe7e19af3736f6c46951c0c539183f8f43d9c0d6992de56328bec' 
  AND token = 'mRSlDQ7HyNZMJEMR8ZiNcuutGvwVqD3edosgcnfcKKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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