SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '829f626ba58b47fe5924149e6de527e4e3782e235d928000e05d8973ea8942fd' 
  AND token = 'PbTU/bMYcr0NKY4kO2Tyt+lRgjGtmcCx2h2nKYfwjLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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