SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cda68bf444856762406c4b5df6918482491bc8b3abd185b027c76d27e766363' 
  AND token = 'JvyLrPr84CVydpuAUPbscmubTDPrF+I+kdLkiNTUjFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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