SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5bf70de1cc4ba2c0a82a6c61bff22dd864af376309117dd9609959151bf2f67' 
  AND token = 'sRyR4umA4gwMWPmKoWFk+kIvvW65BmWVCFCWUIZm4hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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