SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3ee2a7abd6a91a873ad08c250672f3f4afc2f673df2a33b8f4343a8c421af3c' 
  AND token = 'MN25AVAZZXDPiPkT1hRj4U/2yvLFBrjwebTtbFK2LtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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