SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92a423e1621f0fee3e82cc857f1dad7f322823dad999762a3be5ba8756025ac8' 
  AND token = 'QTZ3bBWHYAEXjPG0ZQYcwAJYXVgKBPlKYRigHKxQeQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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