SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ef25c645ea509e007bae73ff37d710298ecb8c1398635f7af5f621ccda311e0' 
  AND token = 'mCVaIwIuS5Bw/KPRKLfBwtNSi5Bsv/m4mweuaGYshyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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