SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4213eb85a11b2da57d66d48be13711b21266829ac1bca0d10c8ce8faefd18f98' 
  AND token = 'Fk69TYdG1r3Xi4WyIVsA2lFEhkVwzmasFzHDkYJbfy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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