SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b81a3e87b43ca16a6e3714e3959063db75c6df9c0bec3501cf8b91d1d5fe699' 
  AND token = 'kCRVCmNFicXDsOEYLVrq6I7UYJyaLEG/V8MoZts1iyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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