SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c53614a4d0046c9edee9a704bf9b426477923a50b84109dbde9a595703a5620' 
  AND token = 'b/CU3WurnFOEKkQ6wLmQkg3DIRP3dDMD4HywonZgJHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}