SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feb465fc4814026aa373d35e89dbe8f1607b3de71fdabfea47777288e3bf036f' 
  AND token = 'ega4k7+iVGVGM+7SmipnlvjNG/LqrlHFORjASi6w8PE=' 
  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"
    }
  }
}