SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b501929b1e37b037293ab59c5a03706512529b646c673806fe7576de071ea27d' 
  AND token = '+0mKJvAPOaIYCo5S0gxhfWrJC0Z5eyXjGJL03nJqlUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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