SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a45c14c962913aa22005eadaf2571793eeb9cbbb68559cbdccc3a6ec971bf1f1' 
  AND token = 'l6WZvlaTtQDN4Rkd3DMBV9r+wrUsSj8mM7uyuwdhIiE=' 
  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"
    }
  }
}