SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8afb508b1f0097fb1388d7fbad8283dc4346594f7c5e6c9567bc92a449fec504' 
  AND token = 'Uj7fajHfxLas8zDtUdzu7IuZaAgAFsLt3IinqAPIgyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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